This application claims the benefit of priority under 35 U.S.C. §119 of EP Application 05110647.4 filed Nov. 11, 2005, the contents of which are hereby incorporated by reference.
1 . Field of the Invention
The present invention is directed to instruments, devices and methods for use in the fields of nucleic acid isolation and amplification.
2 . Description of Related Art
Devices for catching drops for various applications are known in the art. WO200071330 describes a semi-automated lamination process and apparatus for laminating spherical and cylinder power ophthalmic lens blanks in a properly oriented alignment of the lens blanks. Herein, the apparatus may comprise a drip tray with a removable insert for catching a hardenable liquid adhesive from a syringe, which is located on the carriage underneath the syringe applicator at a distinct operating position. In particular, the drip tray is actively transported underneath the syringe for receiving the expended liquid adhesive, when the syringe is undergoing priming steps in order to reduce the occurrence of bubbles. Herein, the drip tray is not used to prevent the contamination of the apparatus by unintentional discharge of liquid, but as a reservoir for expended liquid during priming of the syringe. Furthermore, the movement of the drip tray is not mechanically coupled to the vertical movement of the syringe.
In the field of nucleic acid research and sample preparation drop catchers have been used in instruments such the MagNA Pure Compact or the MagNA PureLC (both manufactured by Roche Applied Science) to prevent unintentional discharge of liquid from the pipetting device. Both instruments contain oblong drop catchers, which are carried by the upper side of the magnet unit. Whenever the pipetting device is moved over the reagent/sample stage by a first actuator, the liquid drop catcher is actively placed underneath the pipetting device by a second actuator to prevent possible drops falling from the pipetting device onto the instrument and thereby contaminating the reagent/sample stage, reagents or other samples.
EP 1110609 discloses a multi-chamber assembly and a pipette assembly for processing fluid samples containing nucleic acids comprising a contamination guard for preventing fluid extracted from a first chamber dispersing into a second chamber. The pipette assembly has one movement action along the line of a row of sample chambers with an up and down movement action conducted by a first movement unit, while a second movement unit shifts the contamination guard in relation to the sample chambers. In one particular embodiment the contamination guard may also be attached to the pipette assembly. This embodiment has the disadvantage that the opening of the pipette assembly is not covered by the contamination guard when the pipette assembly is moved and therefore, may not receive and incorporate liquids escaping from the opening of the pipette assembly or dripping from the outer walls of the pipette assembly when the pipette assembly is withdrawn from the multi-chamber assembly.
EP 1508809 discloses a sample analyzer for nucleic acid detection comprising a droplet removing member. The movement of the droplet removing member is not mechanically coupled to the movement of the dispensing unit and therefore, necessitates the use of two separate actuators for driving these movements.
For integrated systems drop catchers as used in the MagNA Pure Compact, the MagNA PureLC instruments or as disclosed in EP 1110609 and EP 1508809 have the common disadvantage that an active movement of the drop catcher is performed by a second actuator independent of the movement of the pipetting device, which is conducted by a first actuator. However, the integration of a second actuator on a pipetting head is very space consuming and also very costly. Furthermore, a drop catcher as described before is not useful, when more than one pipetting device is mounted on a pipetting head and when these pipetting devices shall operate independently from another without increasing the potentiality of contamination of the instrument.